US10196732B2 - Mask assembly for thin film deposition that includes a partially etched area and method of manufacturing the mask assembly - Google Patents

Abstract

A mask assembly for thin film deposition, the mask assembly, including a mask frame having an opening; a mask coupled to the mask frame and having a first surface facing a substrate and a second surface opposite to the first surface, a plurality of deposition pattern portions, and a rib between the adjacent deposition pattern portions, the mask having a partially etched area, the plurality of deposition pattern portions being within the partially etched area; and a partial etching extension portion in an outer portion of an area corresponding to the plurality of deposition pattern portions.

Description

CROSS-REFERENCE TO RELATED APPLICATION

Korean Patent Application No. 10-2014-0164424, filed on Nov. 24, 2014, in the Korean Intellectual Property Office, and entitled: “Mask Assembly For Thin Film Deposition and Method Of Manufacturing The Mask Assembly,” is incorporated by reference herein in its entirety.

BACKGROUND

1. Field

One or more exemplary embodiments relate to mask assemblies for thin film deposition and methods of manufacturing the mask assemblies.

2. Description of the Related Art

An organic light emitting display apparatus including a thin film transistor (TFT) may be used in mobile devices such as smartphones, tablet personal computers, laptop computers, digital cameras, camcorders, or portable information terminals, or electronic devices such as super-slim TVs or signboards.

SUMMARY

Embodiments may be realized by providing a mask assembly for thin film deposition, the mask assembly, including a mask frame having an opening; a mask coupled to the mask frame and having a first surface facing a substrate and a second surface opposite to the first surface, a plurality of deposition pattern portions, and a rib between adjacent deposition pattern portions, the mask having a partially etched area, the plurality of deposition pattern portions being within the partially etched area; and a partial etching extension portion in an outer portion of an area corresponding to the plurality of deposition pattern portions.

The deposition pattern portions may include a plurality of slits that pass through the mask in a thickness direction of the mask.

The partial etching extension portion may only be in an area of the mask etched without passing through the mask.

The deposition pattern portions may be spaced apart from one another in a length direction of the mask, and the partially etched area may extend from a first end to a second end opposite to the first end in the length direction of the mask.

The partial etching extension portion may extend from the outer portion of the area corresponding to the plurality of deposition pattern portions to an edge of the partially etched area.

The deposition pattern portions may be spaced apart from one another in a length direction of the mask, and the partially etched area may independently be formed for each area corresponding to the deposition pattern portions.

The partial etching extension portion may extend from each outer portion of the area corresponding to the deposition pattern portions to an edge of each of the partially etched areas.

The rib between the adjacent deposition pattern portions may connect the adjacent deposition pattern portions, and the rib may be between partial etching extension portions that extend from adjacent deposition pattern portions in opposite directions to each other.

The rib may be thicker than the partial etching extension portion.

The partially etched area may be an area formed by etching the mask from the second surface to the first surface of the mask so that a portion of the mask has a smaller thickness than other portions of the mask.

The first surface may contact a substrate for deposition, to be patterned.

The mask may be at least one division mask.

Embodiments may be realized by providing a method of manufacturing a mask assembly for thin film deposition, the method including preparing a mask having a first surface facing a substrate and a second surface opposite to the first surface; forming a partially etched area in the mask; forming a plurality of deposition pattern portions in the partially etched area; and forming a partial etching extension portion in an outer portion of an area corresponding to the plurality of deposition pattern portions.

Forming the partially etched area may include coating at least the first surface of the mask with a first photosensitive layer and exposing the first photosensitive layer to light and developing and etching the first photosensitive layer.

Forming the partial etching extension portion may include etching the mask from the outer portion of the area corresponding to the plurality of deposition pattern portions to an edge of the partially etched area without passing through the mask.

The partially etched area may extend from a first end to a second end opposite to the first end in a length direction of the mask, and the deposition pattern portions may be spaced apart from one another in the length direction of the mask.

The partially etched area may independently be formed for each area where the deposition pattern portions are formed, and the plurality of deposition pattern portions may be formed in each of a plurality of partially etched areas.

The deposition pattern portions may be formed by coating at least the second surface of the mask with a second photosensitive layer, exposing the second photosensitive layer to light and developing the second photosensitive layer, and formed as slits that pass through the mask in a thickness direction of the mask by performing at least one etching operation.

The second photosensitive layer may be patterned both on the first surface and the second surface of the mask, and the deposition pattern portions may be formed by performing a two-step etching operation on the first surface and the second surface of the mask.

The second photosensitive layer may be patterned on one of the first surface and the second surface of the mask, and the deposition pattern portions may be formed by performing a one-step etching operation on the one of the first and second surfaces of the mask.

BRIEF DESCRIPTION OF THE DRAWINGS

Features will become apparent to those of skill in the art by describing in detail exemplary embodiments with reference to the attached drawings in which:

FIG. 1 illustrates a perspective view of a mask assembly for thin film deposition, according to an embodiment;

FIG. 2A illustrates a perspective view of a division mask according to an embodiment;

FIG. 2B illustrates a plan view of the division mask ofFIG. 2A;

FIG. 3 illustrates a cross-sectional view of a photosensitive layer formed on the division mask ofFIG. 2A;

FIGS. 4A through 4J sequentially illustrate a method of manufacturing a mask according to an embodiment;

FIGS. 5A through 5G sequentially illustrate a method of manufacturing a mask according to an embodiment;

FIG. 6 illustrates a plan view of a mask according to an embodiment;

FIG. 7 illustrates a cross-sectional view of a portion of the mask ofFIG. 6;

FIG. 8 illustrates a structural diagram of deposition of a thin film on a substrate by using a mask assembly according to an embodiment; and

FIG. 9 illustrates a cross-sectional view of a sub-pixel of an organic light emitting display apparatus according to an embodiment.

DETAILED DESCRIPTION

Example embodiments will now be described more fully hereinafter with reference to the accompanying drawings; however, they may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey exemplary implementations to those skilled in the art.

In the drawing figures, the dimensions of layers and regions may be exaggerated for clarity of illustration. It will also be understood that when a layer or element is referred to as being “on” another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may also be present. Further, it will be understood that when a layer is referred to as being “under” another layer, it can be directly under, and one or more intervening layers may also be present. In addition, it will also be understood that when a layer is referred to as being “between” two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present.

As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.

It will be understood that although the terms “first”, “second”, etc., may be used herein to describe various components, these components should not be limited by these terms. These components are only used to distinguish one component from another.

The terms used in the present specification are merely used to describe particular embodiments, and are not intended to limit the disclosure. An expression used in the singular encompasses the expression of the plural, unless it has a clearly different meaning in the context. In the present specification, it is to be understood that the terms such as “including” or “having,” etc., are intended to indicate the existence of the features, numbers, steps, actions, components, parts, or combinations thereof disclosed in the specification, and are not intended to preclude the possibility that one or more other features, numbers, steps, actions, components, parts, or combinations thereof may exist or may be added.

One or more embodiments will be described below in more detail with reference to the accompanying drawings. Those components that are the same or are in correspondence are rendered the same reference numeral regardless of the figure number, and redundant explanations are omitted.

FIG. 1 illustrates a perspective view of amask assembly100 for thin film deposition, according to an embodiment.

Referring toFIG. 1, themask assembly100 may include amask frame110 and amask130 having a plurality of division masks120.

Themask frame110 may have anopening115 and may include a plurality offrames111 through114 surrounding theopening115. The plurality offrames111 through114 may be connected to one another.

Themask frame110 may include afirst frame111 and asecond frame112 that face each other in an X direction and extend in a Y direction and athird frame113 and afourth frame114 that face each other in the Y direction and extend in the X direction. Thefirst frame111, thesecond frame112, thethird frame113, and thefourth frame114 may be connected to one another to form a rectangular frame. Themask frame110 may be formed of a material that deforms little by welding of themask130, for example, of a metal having a high rigidity.

Themask130 may be mounted on themask frame110. In order to form a precise deposition pattern, adhesive properties between themask130 and asubstrate140 installed on themask130 may be increased, and shadows may be reduced. Themask130 may be manufactured by using a thin sheet. Themask130 may be formed of a material such as stainless steel, invar, nickel (Ni), cobalt (Co), a nickel alloy, or a nickel-cobalt alloy.

Themask130 may include a plurality of division masks120 that are separate from one another in the Y direction, and sagging thereof, for example, due to their own weight, may be prevented. The division masks120 may be sticks. According to an embodiment, themask130 may have a structure in which, for example, the width of themask130 may be smaller than a length thereof, which may be a tensile direction.

The division masks120 may be separated from one another in a direction (Y direction) across the tensile direction (X direction). For example, the plurality of division masks120 may be continuously arranged between thethird frame113 and thefourth frame114, and two ends of each of the division masks120 may be respectively fixed to thefirst frame111 and thesecond frame112 by welding. The plurality of division masks120 may cover theopening115.

FIG. 2A illustrates a perspective view of adivision mask200 according to an embodiment, andFIG. 2B illustrates a plan view of thedivision mask200 ofFIG. 2A.

Referring toFIGS. 2A and 2B, thedivision mask200 may be a thin metal plate. Thedivision mask200 may have afirst surface201 facing the substrate140 (seeFIG. 1) and asecond surface202 opposite to thefirst surface201. A plurality ofdeposition pattern portions211 may be formed in thedivision mask200. Thedeposition pattern portions211 may be spaced apart from one another in a length direction of the division mask200 (X direction).

Each of thedeposition pattern portions211 may include a plurality ofslits212. Theslits212 may pass through thedivision mask200 in a thickness direction of thedivision mask200, e.g., may pass through an entirety of the thickness of thedivision mask200. According to the present embodiment, theslits212 are strip-shaped. In an embodiment, theslits212 may be, for example, dotted patterns.

According to an embodiment, each of thedeposition pattern portions211 may correspond to a unit display apparatus such as a compact mobile device. In an embodiment, a plurality of division masks200 may correspond to one large-sized display apparatus.

Arib213 may be formed between the adjacentdeposition pattern portions211. Therib213 may connect adjacentdeposition pattern portions211 along the length direction of the division mask200 (X direction). A dummy deposition pattern portion (not shown) may be further formed in therib213. The dummy deposition pattern portion may include a slit or may be a partially etched area, e.g., a half-etched area. Throughout the specification, the phrase “half-etched area” may refer to an embodiment of a “partially etched area”.

A half-etchedarea220 may be formed in thedivision mask200.

The half-etchedarea220 may be an area formed by etching thedivision mask200 in a thickness direction of thedivision mask200 to a predetermined depth, e.g., a depth of half the thickness of thedivision mask200. According to an embodiment, the half-etchedarea220 may be formed by etching thedivision mask200 by a thickness, e.g., a half thickness, of thedivision mask200. The half-etchedarea220 may not pass through thedivision mask200.

The half-etchedarea220 may extend from afirst end214 of thedivision mask200 to asecond end215 opposite to thefirst end214 in a length direction of thedivision mask200. The plurality ofdeposition pattern portions211 and a plurality ofribs213 may be disposed within the half-etched area20. Afirst area216 between the half-etchedarea220 and thefirst end214 and asecond area217 between the half-etchedarea220 and thesecond end215 may be welded areas. Thefirst area216 and thesecond area217 may not be half-etched.

A partialetching extension portion221, e.g., a halfetching extension portion221, may be formed in the half-etchedarea220. Throughout the specification, the phrase “half etching extension portion” may refer to an embodiment of a “partial etching extension portion”.

For example, the halfetching extension portion221 may extend from an outer portion of anarea223 where the plurality ofdeposition pattern portions211 are formed, e.g., an outer portion of anarea223 corresponding to the plurality ofdeposition pattern portions211, to an edge of the half-etchedarea220. The halfetching extension portion221 may be an area formed by etching thedivision mask200 in a thickness direction of thedivision mask200. Unlike thedeposition pattern portions211, slits passing through thedivision mask200 may not be formed in the halfetching extension portion221.

In a width direction of the division mask200 (Y direction), a portion between the halfetching extension portion221 and anedge218 of thedivision mask200 may not be half-etched.

A pattern of thedeposition pattern portions211 may be formed by using a photosensitive layer.

If the half-etchedarea220 is formed in thedivision mask200, a photosensitive layer may not be properly attached to the edge of the half-etchedarea220. The photosensitive layer may not be properly attached, for example, due to a step between a portion of thedivision mask200 that may not be half-etched and the half-etching area220. If an etching solution penetrates into thearea223 where thedeposition pattern portions211 are formed, through space where no photosensitive layer is attached, pattern defects may be caused.

According to the present embodiment, the halfetching extension portion221 may be formed in the area where thedeposition pattern portions211 are formed, and pattern defects may be prevented.

FIG. 3 illustrates a cross-sectional view of a photosensitive layer formed on thedivision mask200 ofFIG. 2A. Referring toFIG. 3, thedivision mask200 may have afirst surface201 and asecond surface202 that is opposite to thefirst surface201. Thefirst surface201 may contact a substrate for deposition, e.g., a substrate to be deposited upon, to be patterned.

A half-etchedarea220 may be formed in thedivision mask200. The half-etchedarea220 may be an area formed by etching thedivision mask200 from thesecond surface202 to thefirst surface201, and a portion of thedivision mask200 may have a smaller thickness than other portions thereof.

A halfetching extension portion221 may be formed in the half-etchedarea220. The halfetching extension portion221 may extend from an outer portion of an area A where a plurality of deposition pattern portions are formed to an edge B of the half-etchedarea220. The area A may correspond to thearea223 where the plurality ofdeposition pattern portions211 are spaced apart from one another at predetermined distances.

Aphotosensitive layer301 may be formed on thesecond surface202 of thedivision mask200. Thephotosensitive layer301 may be used to form the deposition pattern portions211 (seeFIG. 2A). Thephotosensitive layer301 may be a dry film resist (DFR). According to an embodiment, thephotosensitive layer301 may be a liquid photoresist.

When attaching thephotosensitive layer301 to thesecond surface202 of thedivision mask200,space302 where thephotosensitive layer301 may be not attached may be formed at an edge of the half-etchedarea220.

According to the present embodiment, the halfetching extension portion221 may be formed outside the area A where deposition pattern portions are formed. The halfetching extension portion221 may correspond to the edge B of the half-etchedarea220. Thespace302 may be formed in the halfetching extension portion221. As the halfetching extension portion221 is formed, no space may be formed in the area A where a plurality of deposition pattern portions are formed.

As described above, as the halfetching extension portion221 is formed at the edge B of the half-etchedarea220, the half-etchedarea220 may extends over the area A where a plurality of deposition pattern portions are formed. In the area A where a plurality of deposition pattern portions are formed, thephotosensitive layer301 may completely contact thesecond surface202 of thedivision mask200. Accordingly, an etching solution may not be able to penetrate into the area A where a plurality of deposition pattern portions are formed, and the deposition pattern portions may be precisely formed.

FIGS. 4A through 4J sequentially illustrate a method of manufacturing amask400 according to an embodiment.

Referring toFIG. 4A, themask400 may be prepared. According to an embodiment, themask400 may be a division mask. Themask400 may include afirst surface401 facing a substrate to be deposited, e.g., to be deposited upon, and asecond surface402 opposite to thefirst surface401.

Referring toFIG. 4B, a firstphotosensitive layer403 may be formed on thesecond surface402 of themask400. According to the present embodiment, thephotosensitive layer403 may be a dry film register (DFR). Thephotosensitive layer403 may be attached to thesecond surface402 of themask400 by using a laminating process.

Referring toFIG. 4C, thephotosensitive layer403 may be exposed to light and developed. Then, thephotosensitive layer403 may be etched.

Referring toFIG. 4D, by etching thephotosensitive layer403, a half-etchedarea404 may be formed in themask400. The half-etchedarea404 may be an area formed by etching themask400 by a thickness, e.g., half of a thickness, of themask400 in a thickness direction of themask400. The half-etchedarea404 may be formed at a predetermined depth from thesecond surface402 of themask400, e.g., a depth of half the thickness of themask400. The half-etchedarea404 may be formed between afirst end405 and asecond end406 of themask400 in a length direction of themask400. The half-etchedarea404 may include an area A where a plurality of deposition pattern portions are formed. During an etching process, a plurality of deposition pattern portions may be spaced apart from one another at predetermined distances in the area A.

A halfetching extension portion407 may be formed in the half-etchedarea404. The halfetching extension portion407 may extend from an outer portion of the area A where a plurality of deposition pattern portions are formed to an edge B of the half-etchedarea404. The halfetching extension portion407 may correspond to the edge B of the half-etchedarea404. The halfetching extension portion407 may be an area that may be etched without passing through themask400.

Referring toFIG. 4E, a firstphotosensitive layer408 may be formed on thefirst surface401 of themask400. A secondphotosensitive layer409 may be formed on the second surface420 of themask400. According to the present embodiment, the firstphotosensitive layer408 and the secondphotosensitive layer409 may be dry film registers.

The firstphotosensitive layer408 and the secondphotosensitive layer409 may be respectively attached to thefirst surface401 and thesecond surface402 of themask400 by using a vacuum lamination process. The firstphotosensitive layer408 may be attached to the entirefirst surface401 of themask400. The secondphotosensitive layer409 may cover both the area A where deposition pattern portions of themask400 are formed and the edge B of themask400.

Referring toFIG. 4F, the firstphotosensitive layer408 and the secondphotosensitive layer409 may be exposed to light and developed. According to an embodiment, the firstphotosensitive layer408 and the secondphotosensitive layer409 may cover the halfetching extension portion407.

According to the present embodiment, a pattern of the deposition pattern portions may be formed using a two-step etching process in which an etching process may be performed on two sides of themask400.

Referring toFIG. 4G, the firstphotosensitive layer408 may be etched.

The first etching step may be performed on thefirst surface401 of themask400, which may face a substrate to be deposited, e.g., to be deposited upon. In the first etching step, themask400 may be etched from thefirst surface401 to a predetermined depth. The halfetching extension portion407 may be covered by the firstphotosensitive layer408, and etching may not be performed on the halfetching extension portion407.

Referring toFIG. 4H, aresin410 may be coated on thefirst surface401 of themask400 where the first etching step may be performed. Theresin410 may cover an area of themask400 etched from thefirst surface401. According to an embodiment, theresin410 may be omitted.

Referring toFIG. 4I, the secondphotosensitive layer409 may be etched.

The second etching step may be performed on thesecond surface402 of themask400. In the second etching step, themask400 may be etched from thesecond surface402 to a predetermined depth. An area etched by the second etching step may be vertically in line with the area etched by the first etching step, with respect to themask400. The halfetching extension portion407 may be covered by the secondphotosensitive layer409, and etching may not be performed on the halfetching extension portion407.

Referring toFIG. 4J, by performing the first and second steps of etching,deposition pattern portions411 that pass through themask400 in a thickness direction of themask400 may be formed in the half-etchedarea404. Thedeposition pattern portions411 may be spaced apart from one another by predetermined distances in a length direction of themask400. As described above, by performing two-step etching on thefirst surface401 and thesecond surface402 of themask400, thedeposition pattern portions411 may be formed to have a slit shape.

The halfetching extension portion407 may be covered by the firstphotosensitive layer408 and the secondphotosensitive layer409 during the two-step etching, and may not pass through themask400.

As described above, when forming the plurality ofdeposition pattern portions411 in the half-etchedarea404, the halfetching extension portion407 may be formed in an outer portion of the area A where thedeposition pattern portions411 are formed, and penetration of an etching solution into an area where thedeposition pattern portions411 are formed may be prevented. Accordingly, themask400 having a uniform thickness and thedeposition pattern portions411 having a precise pattern may be manufactured.

FIGS. 5A through 5G sequentially illustrate a method of manufacturing amask500 according to an embodiment.

Referring toFIG. 5A, themask500 may be prepared. According to an embodiment, themask500 may be a division mask. Themask500 may include afirst surface501 facing a substrate to be deposited, e.g., to be deposited upon, and asecond surface502 opposite to thefirst surface501.

Referring toFIG. 5B, in themask500, a half-etchedarea504 may be formed by using a photosensitive layer and by performing exposure, development, and etching on the photosensitive layer. The half-etchedarea504 may be an area formed by etching themask500 by a thickness, e.g., a half thickness, of themask500. The half-etchedarea504 may be formed to a predetermined depth, e.g., a depth of half the thickness of themask500, from thesecond surface502 of themask500.

The half-etchedarea504 may be formed between afirst end505 and asecond end506 in a length direction of themask500. The half-etchedarea504 may be a groove formed in the length direction of themask500. The half-etchedarea504 may not pass through themask500 in a thickness direction of themask500. The half-etchedarea504 may include an area A where deposition pattern portions are formed. In the area A, a plurality of deposition pattern portions may be spaced apart from one another at predetermined distances during an etching operation.

A halfetching extension portion507 may be formed in the half-etchedarea504. The halfetching extension portion507 may extend from an outer portion of the area A where a plurality of deposition pattern portions are formed to an edge B of the half-etchedarea504.

Referring toFIG. 5C, aphotosensitive layer509 may be formed on thesecond surface502 of themask500. Thephotosensitive layer509 may be a dry film register. Thephotosensitive layer509 may be attached to thesecond surface502 of themask500 by using a vacuum lamination process. Thephotosensitive layer509 may cover both the area A where deposition pattern portions are formed and the edge B of themask500.

Referring toFIG. 5D, thephotosensitive layer509 may be exposed to light and developed. According to an embodiment, thephotosensitive layer509 may cover the halfetching extension portion507.

Referring toFIG. 5E, aresin510 may be coated on thefirst surface501 of themask500. During an etching operation, theresin510 may protect thefirst surface501 of themask500.

Referring toFIG. 5F, thephotosensitive layer509 may be etched. For example, only one etching step may be performed.

For example, themask500 may be etched from thesecond surface502. The halfetching extension portion507 may cover thephotosensitive layer509, and etching may not be performed on the halfetching extension portion507.

Referring toFIG. 5G, as the one-step etching operation is performed,deposition pattern portions511 that pass through themask500 in a thickness direction of themask500 may be formed in the half-etchedarea504. As described above, by performing an etching operation only once from thesecond surface502 of themask500, thedeposition pattern portions511 may be formed to have a slit shape.

The halfetching extension portion507 may be covered during the one-step etching operation, and may not pass through themask500.

As described above, when forming a plurality ofdeposition pattern portions511 in the half-etchedarea504, as the halfetching extension portion507 is formed in an outer portion of the area A where thedeposition pattern portions511 are formed, penetration of an etching solution into the area A where thedeposition pattern portions511 are formed may be prevented.

FIG. 6 illustrates a plan view of amask600 according to an embodiment.

Referring toFIG. 6, themask600 may have afirst surface601 and asecond surface602 opposite to thefirst surface601. Thefirst surface601 may contact a substrate for deposition, e.g., a substrate to be deposited upon, which is to be patterned. According to an embodiment, themask600 may be a division mask.

A plurality ofdeposition pattern portions611 may be formed on themask600. Thedeposition pattern portions611 may be spaced apart from one another in a length direction of the mask600 (X direction). Each of thedeposition pattern portions611 may include a plurality ofslits612. Theslits612 may pass through themask600 in a thickness direction of the mask.

Arib613 may be formed between the adjacentdeposition pattern portions611. Therib613 may connect adjacentdeposition pattern portions611 arranged next to each other in a length direction of the mask600 (X direction). Therib613 may further include a dummy deposition pattern portion (not shown). The dummy deposition pattern portion may include a slit or may be a half-etched area.

A half-etchedarea620 may be formed in themask600.

The half-etchedarea620 may be an area formed by etching themask600 in a thickness direction by a predetermined depth, e.g., a depth of half the thickness of theetching mask600. The half-etchedarea620 may be an area formed by etching themask600 by a thickness, e.g., half a thickness, of themask600. The half-etchedarea620 may not pass through themask600.

The plurality ofdeposition pattern portions611 may be located within the half-etchedarea620. The half-etchedarea620 may be formed in each area where the plurality ofdeposition pattern portions611 are formed. The half-etchedarea620 may be arranged at predetermined distances in a length direction of themask600. A plurality of half-etchedareas620 may be independently formed for each area where thedeposition pattern portions611 are formed.

Afirst area616 between afirst end614 of themask600 and ahalf etching area620 in a first outermost portion and asecond area617 between asecond end615, which is opposite to thefirst end614, and a half-etchedarea620 in a second outermost portion in a length direction of themask600 may be welded areas. Thefirst area616 and thesecond area617 may not be half-etched.

In each of the half-etchedareas620, a halfetching extension portion621 may be formed. The halfetching extension portion621 may extend out beyond anarea623 where thedeposition pattern portions611 are formed. The halfetching extension portion621 may be an area formed by etching the mask in a thickness direction of themask600. Unlike thedeposition pattern portions611, the halfetching extension portion621 may not pass through themask600.

According to an embodiment, therib613 may be disposed between halfetching extension portions621 that extend from adjacentdeposition pattern portions611 in opposite directions to each other. As therib613 is not etched, therib613 may be thicker than the halfetching extension portion621.

In a width direction of the mask600 (Y direction), an area the halfetching extension portion621 and anedge618 of themask600 may not be half-etched.

FIG. 7 illustrates a cross-sectional view of a portion of themask600 ofFIG. 6.

According to an embodiment, the portion of themask600 may correspond to one of a plurality ofdeposition pattern portions611 arranged in a length direction of themask600.

Referring toFIG. 7, themask600 may be etched to form thedeposition pattern portions611. When attaching aphotosensitive layer701 to thesecond surface602 of themask600,space702 where thephotosensitive layer701 may not be properly attached may be generated at an edge B of the half-etchedarea620.

According to the present embodiment, in themask600, a halfetching extension portion621 may be formed in an outer portion of an area C where a plurality of deposition pattern portions are formed. The halfetching extension portion621 may extend from an outer portion of the area C where deposition pattern portions are formed to an edge D of the half-etchedarea620.

Even if thespace702 is formed as thephotosensitive layer701 is properly attached to themask600, thespace702 may be disposed in the halfetching extension portion621. In the area C where a plurality of deposition pattern portions are formed, thephotosensitive layer701 may completely contact thesecond surface602 of themask600, and an etching solution may not penetrate into the area C where a plurality of deposition pattern portions are formed.

FIG. 8 illustrates a structural diagram of deposition of a thin film on a substrate by using amask assembly800 according to an embodiment.

Referring toFIG. 8, avacuum chamber801 may be prepared using themask assembly800 to deposit an organic emissive layer or an electrode of an organic light emitting display apparatus.

Adeposition source802 may be disposed under thevacuum chamber801, and themask assembly800 may be installed above thedeposition source802. Themask assembly800 may include thedivision mask200 illustrated inFIG. 2. Thedivision mask200 may include at least one division mask. Thedivision mask200 may be disposed on amask frame803. Asubstrate805 for deposition, e.g., asubstrate805 to be deposited upon, may be disposed on thedivision mask200. An additional supportingmember806 that fixes themask assembly800 may be further included at an edge of themask assembly800.

Hereinafter, how a deposition material is deposited on thesubstrate805 will be described briefly.

First, themask assembly800 may be fixed to the supportingmember806, and thesubstrate805 for deposition, e.g., thesubstrate805 to be deposited upon, may be located on thedivision mask200.

Next, by spraying a deposition material from thedeposition source802 disposed under thevacuum chamber801 onto themask assembly800, the deposition material may be deposited on a surface of thesubstrate805, for example, due to the deposition pattern portions211 (seeFIG. 2) formed on thedivision mask200.

FIG. 9 illustrates a cross-sectional view of a sub-pixel of an organic light emittingdisplay apparatus900, which may be formed by deposition performed by using themask200, according to an embodiment.

Referring toFIG. 9, the organic light emittingdisplay apparatus900 may include adisplay substrate901. Thedisplay substrate901 may be formed of a flexible insulation material or an insulation material having rigidity. Thedisplay substrate901 may be transparent, semi-transparent or opaque.

Abarrier layer902 may be formed on thedisplay substrate901. Thebarrier layer902 may cover the entire upper surface of thedisplay substrate901. Thebarrier layer902 may include an inorganic layer or an organic layer.

A thin film transistor (TFT) may be formed on thebarrier layer902. A semiconductoractive layer903 may be formed on thebarrier layer902. Asource area904 and adrain area905 may be formed on the semiconductoractive layer903 by doping with an N-type impurity ion or a P-type impurity ion. An area between thesource area904 and thedrain area905 may be achannel area906 which may not be doped with an impurity.

Agate insulation layer907 may be deposited on the semiconductoractive layer903. Thegate insulation layer907 may include an inorganic layer such as a silicon oxide, a silicon nitride or a metal oxide. Thegate insulation layer907 may be a single layer or a multi-layer.

Agate electrode908 may be formed on a predetermined area of thegate insulation layer907. Thegate electrode908 may include a single layer or a multi-layer formed of, for example, Au, Ag, Cu, Ni, Pt, Pd, Al, Mo, or Cr. Thegate electrode908 may include an alloy such as Al:Nd or Mo:W.

Aninterlayer insulation layer909 may be formed on thegate electrode908. Theinterlayer insulation layer909 may include an inorganic layer such as a silicon oxide or a silicon nitride, or an organic layer.

Asource electrode910 and adrain electrode911 may be formed on theinterlayer insulation layer909. For example, a contact hole may be formed in thegate insulation layer907 and theinterlayer insulation layer909 by selectively removing portions thereof, and thesource electrode910 may be electrically connected to thesource area904 and thedrain electrode911 may be electrically connected to thedrain area905 through the hole.

Aprotection layer912 such as a passivation layer and/or a planarization layer may be formed on thesource electrode910 and thedrain electrode911. Theprotection layer912 may include an inorganic layer such as a silicon oxide or a silicon nitride or an organic layer such as acryl, polyimide, or benzocyclobutene (BCB).

An organic light emitting device (OLED) may be formed on the TFT.

The OLED may be formed on theprotection layer912. The OLED may include afirst electrode913, anintermediate layer922 including an organic emissive layer, and asecond electrode915.

Apixel defining layer914 may cover theprotection layer912 and a portion of thefirst electrode913. Thepixel defining layer914 may be formed of an organic layer or an inorganic layer. Thepixel defining layer914 may be formed of a single layer or a multi-layer.

Holes and electrons respectively injected from thefirst electrode913 and thesecond electrode915 of the OLED may combine in the organic emissive layer of theintermediate layer922, and light may be emitted.

Theintermediate layer922 may include the organic emissive layer. According to an embodiment, theintermediate layer922 may further include, in addition to the organic emissive layer, at least one of a hole injection layer (HIL), a hole transport layer (HTL), an electron transport layer (ETL), and an electron injection layer (EIL). In an embodiment, and theintermediate layer922 may include an organic emissive layer and also other various functional layers.

Thesecond electrode915 may be formed on theintermediate layer922. Thesecond electrode915 may generates an electrical field with thefirst electrode913, and light may be emitted from theintermediate layer922. Thefirst electrode913 may be patterned in each pixel, and thesecond electrode913 may be formed so as to apply a common voltage to all pixels.

Thefirst electrode913 and thesecond electrode915 may include a transparent electrode or a reflective electrode.

Thefirst electrode913 may function as an anode and may be formed of various conductive materials. While thefirst electrode913 may be a transparent electrode, it may also be formed of a reflective electrode. Thesecond electrode915 may function as a cathode. Like thefirst electrode913, thesecond electrode915 may be formed of a transparent electrode or a reflective electrode.

Anencapsulation substrate916 may be formed above the OLED. Theencapsulation substrate916 may be formed to help protect theintermediate layer922 and other thin layers from, for example, external moisture or oxygen.

Theencapsulation substrate916 may be a rigid glass, a polymer resin, or a flexible film. Theencapsulation substrate916 may be formed by alternately stacking an organic layer and an inorganic layer above the OLED. A plurality of organic layers and a plurality of inorganic layers may be used here.

By way of summation and review, a patterned thin film may be formed in an organic light emitting display apparatus by using a deposition operation. A patterned thin film may be formed by locating on a substrate a mask having the same pattern as that of the patterned thin film to be formed on the substrate and then depositing a raw material of the thin film, on the substrate.

One or more exemplary embodiments include a mask assembly for thin film deposition, and a method of manufacturing the mask assembly.

As described above, according to the one or more of the above exemplary embodiments, a mask having a uniform thickness may be manufactured, and a thin film having a desired pattern may be formed on a substrate.

Example embodiments have been disclosed herein, and although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation. In some instances, as would be apparent to one of skill in the art as of the filing of the present application, features, characteristics, and/or elements described in connection with a particular embodiment may be used singly or in combination with features, characteristics, and/or elements described in connection with other embodiments unless otherwise specifically indicated. Accordingly, it will be understood by those of skill in the art that various changes in form and details may be made without departing from the spirit and scope of the present invention as set forth in the following claims.

Claims (11)

What is claimed is:

1. A mask assembly for thin film deposition, the mask assembly comprising:

a mask frame having an opening;

a mask coupled to the mask frame and having a first surface facing a substrate and a second surface opposite to the first surface, a plurality of deposition pattern portions including a plurality of slits passing through the mask, and a rib between adjacent deposition pattern portions, the mask having a partially etched area having a thickness that is less than a thickness of peripheral areas of the mask, the plurality of deposition pattern portions being within the partially etched area such that the plurality of deposition pattern portions have the thickness that is less than the thickness of the peripheral areas of the mask; and

a partial etching extension portion in an outer portion of an area where the plurality of deposition pattern portions are formed such that the area where the plurality of deposition pattern portions are formed is continuously surrounded by the partial etching extension portion,

wherein a thickness of the area where the plurality of deposition pattern portions are formed is the same as a thickness of the partial etching extension portion, the thickness of the mask at the area where the plurality of deposition pattern portions are formed being a distance in a direction that the slits pass through the mask from the first surface of the mask to the second surface of the mask.

2. The mask assembly as claimed inclaim 1, wherein the partial etching extension portion is located only in an area of the mask etched without passing through the mask.

3. The mask assembly as claimed inclaim 2, wherein:

the deposition pattern portions are spaced apart from one another in a length direction of the mask, and

the partially etched area extends from a first end of the mask to a second end of the mask, the second end of the mask is opposite to the first end of the mask in the length direction of the mask.

4. The mask assembly as claimed inclaim 3, wherein the partial etching extension portion extends from the outer portion of the area where the plurality of deposition pattern portions are formed to an edge of the partially etched area.

5. The mask assembly as claimed inclaim 2, wherein:

the deposition pattern portions are spaced apart from one another in a length direction of the mask, and

the partially etched area is independently formed for each area where the plurality of deposition pattern portions are formed.

6. The mask assembly as claimed inclaim 5, wherein the partial etching extension portion extends from each outer portion of the area where the plurality of deposition pattern portions are formed to an edge of each of the partially etched areas.

7. The mask assembly as claimed inclaim 6, wherein:

the rib between the adjacent deposition pattern portions connects the adjacent deposition pattern portions, and

the rib is between partial etching extension portions that extend from adjacent deposition pattern portions in opposite directions to each other.

8. The mask assembly as claimed inclaim 7, wherein the rib is thicker than the partial etching extension portion.

9. The mask assembly as claimed inclaim 1, wherein the partially etched area is an area formed by etching the mask from the second surface to the first surface of the mask so that the partially etched area has the thickness that is less than the thickness of the peripheral areas of the mask.

10. The mask assembly as claimed inclaim 9, wherein the first surface contacts the substrate for deposition, to be patterned.

11. The mask assembly as claimed inclaim 1, wherein the mask is at least one division mask.

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